hi,
What I learn from experience is, there should have been some thing more you have not moved or some more hack codes still residing in the website. We (you and me) should first check if the codes and pages are hack free and virus free, else when something was working perfectly cannot stop working overnight without a change in the codes or apps. If you think everyting is fine then we need to check the configuration of your new server as well so that it replicates the same as your old server.
So there are a few things that we need to check before we try to work on the codes, else it will kill the pages more and more and you will start loosing patience. You will keep working on errors and errors, one breaks and other works etc,
So, please check the codes if it is working and then may be do a local copy and see if the functionalities are working properly as well,
If you can give a chance, I can check what is the errors and send you a report for you to act upon,
Best regards,
STG